Semaglutide extends female mice lifespan ~100 days

UC Berkeley researchers reported on September 2 that semaglutide, the GLP-1 drug sold as Ozempic and Wegovy, extended lifespan in older female mice and reduced several markers associated with aging. The findings were published in *Nature* and described in a same-day National Institutes of Health release on a study funded by NIH. The work tested semaglutide in 20-month-old female mice, an age the researchers used to model late-life intervention. The authors said the drug mimicked many of the effects of calorie restriction and, on some measures, went beyond them. ### How much longer did the mice live? The NIH said mice treated with semaglutide until the end of life had a median lifespan nearly 100 days longer than untreated mice. UC Berkeley’s summary said the treated animals lived, on average, 100 days longer than controls. Another report on the study said median lifespan was 834 days in the semaglutide group versus 742 days in controls, or about 12% longer. (nature.com) Nature’s related coverage said the effect was shown in one inbred strain of laboratory mice. That matters because the paper did not test a genetically diverse population, and the published results described female mice rather than both sexes. ### What did the researchers actually compare semaglutide against? The study authors compared semaglutide with a 24% calorie-restricted diet matched to the treated animals’ feeding pattern over five months, the NIH said. (nih.gov) The point of that experiment was to test whether the drug’s effects were simply the result of eating less. Danica Chen, the corresponding author and a professor of metabolic biology and nutrition at UC Berkeley, said the results pointed to more than appetite suppression. “These differences point to the possibility that GLP-1 drugs tap into a biological pathway independent of calorie restriction,” Chen said, according to NIH and UC Berkeley. (nature.com) ### Which aging-related changes improved? (nih.gov) The NIH said semaglutide-treated mice showed improved muscle and cognitive function compared with untreated animals. Gene-expression analysis also showed reductions in several hallmarks of natural aging, including increased inflammation and reduced regenerative capacity. UC Berkeley said semaglutide-treated mice also showed higher exploratory behavior, better spatial memory and improved blood-sugar maintenance than calorie-restricted mice. (nih.gov) In the same comparison, calorie-restricted animals had a slower metabolic rate, while metabolic rate in semaglutide-treated mice was largely unchanged. ### Does this mean semaglutide extends human lifespan? (nih.gov) The paper did not show that semaglutide extends human lifespan. NIH described the findings as evidence from healthy older mice that GLP-1 drugs “may slow physiological aging itself,” while Chen said the study could guide future research into semaglutide’s effects on human longevity. (mbn.berkeley.edu) Rafael de Cabo of the NIH’s National Institute on Aging, who wrote a commentary on the study, said the results fit a broader idea that slowing aging could affect many chronic diseases. “Most chronic diseases are deeply rooted in the aging process,” de Cabo said in the NIH release. ### What are the main caveats? The Science Media Centre published outside expert reactions on September 2 that stressed the study’s limits. (nih.gov) Laura Sinclair, a lecturer in healthcare at the University of Exeter, said the work was “a very interesting and thorough study” but noted three major constraints: it was an animal model, it included only females, and dosing began in later life and continued until death. Sinclair also said genetically uniform lab mice can respond differently from more diverse populations and noted that side effects seen in humans, including nausea, were not the same issue in this mouse experiment. She said more studies would be needed before concluding GLP-1 receptor agonists work for aging “for everyone.” (sciencemediacentre.org) ### Where can readers find the study and the next step? The *Nature* paper, titled “Late-life semaglutide treatment slows ageing and extends lifespan in female mice,” was published on September 2. The named participants in the next step are Chen, lead author Yufan Feng, UC Berkeley collaborators, and researchers from the University of Copenhagen and the National Institute on Aging, who the university said will use the findings to guide future work on human longevity. (sciencemediacentre.org) (nature.com)